CVE-2021-30246
📋 TL;DR
The jsrsasign package for Node.js incorrectly validates some invalid RSA PKCS#1 v1.5 signatures as valid, potentially allowing attackers to bypass signature verification. This affects all applications using jsrsasign for cryptographic signature validation. While no practical attacks are currently known, the vulnerability could undermine authentication and integrity mechanisms.
💻 Affected Systems
- jsrsasign
📦 What is this software?
Jsrsasign by Jsrsasign Project
⚠️ Risk & Real-World Impact
Worst Case
Attackers could forge digital signatures to bypass authentication, tamper with signed data, or impersonate legitimate entities in systems relying on RSA signature verification.
Likely Case
Limited impact due to the specific nature of invalid signatures that trigger the bug and lack of known practical exploitation methods.
If Mitigated
Minimal impact if proper signature validation controls and monitoring are in place, though cryptographic integrity would still be compromised.
🎯 Exploit Status
No known practical exploitation methods exist. Exploitation would require generating specific invalid signatures that trigger the bug.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.1.14 and later
Vendor Advisory: https://github.com/kjur/jsrsasign/releases/tag/10.1.13
Restart Required: Yes
Instructions:
1. Update jsrsasign to version 10.1.14 or later using npm: npm update jsrsasign. 2. Restart your Node.js application. 3. Verify the update was successful.
🔧 Temporary Workarounds
Temporarily disable RSA PKCS#1 v1.5 signature validation
allDisable or replace RSA PKCS#1 v1.5 signature validation with alternative methods if possible
🧯 If You Can't Patch
- Implement additional signature validation checks in application code
- Monitor for unusual signature validation patterns in logs
🔍 How to Verify
Check if Vulnerable:
Check package.json or run: npm list jsrsasign | grep jsrsasignCheck Version:
npm list jsrsasignVerify Fix Applied:
Verify installed version is 10.1.14 or later: npm list jsrsasign📡 Detection & Monitoring
Log Indicators:
- Failed signature validation attempts
- Unexpected successful signature validations
Network Indicators:
- Unusual authentication patterns in API calls using signatures
SIEM Query:
Search for application logs containing signature validation errors or unexpected successes